The necessity for accurate installation and alignment of vehicle (e.g., automotive) doors is commonly recognized. One key quality control aspect of modem automobiles is to verify that the doors of the automobile were manufactured, installed and aligned properly so that when one closes the door with a particular force, the door closes securely. Currently, most automobile manufacturers conduct manual tests on a small statistical sample of the vehicles they produce to determine if the doors of such vehicles are properly manufactured, installed and aligned. Typically, the test is not conducted as the vehicle is progressing through the assembly line, but, rather, by removing the vehicle from the assembly line.
Most automobile manufacturers have developed specifications for determining whether their vehicle doors are properly installed and aligned. The specifications generally require that the door achieve a final closing velocity (i.e., the velocity of the door just prior to the door engaging with the latch mechanism) when pushed closed with an initial, constant closing velocity. Several alternative methods have been proposed to test and verify that a door meets these specifications. For example, one such method is to mount a door velocity meter directly on the side of the vehicle adjacent to the door under inspection, i.e., on the body panel immediately behind the door. The door velocity meter measures the velocity of the exterior edge of the door (i.e., opposite the hinge) as the door is being closed. The door is then repeatedly, manually closed, while attempting to achieve and maintain a constant door initial closing velocity. Once the door is pushed in a fashion to achieve the desired door initial closing velocity, the velocity meter is read to determine the final closing velocity, which reading is then compared to an acceptable range. Additionally, the individual performing the test may observe whether or not the door properly engaged the latching mechanism and that the door closed flush with the adjacent body panel.
The difficulties using this approach are considerable. For example, because the test requires the vehicle to be removed from the assembly line, it is quite time-consuming. Additionally, the prior art method requires the door velocity meter to be attached to the vehicle itself and, thus, relies upon physical contact with the surface of the vehicle. Furthermore, because the vehicle must be removed from the assembly line, manufacturers typically only test a small fraction of the vehicles produced, increasing the likelihood that automobiles having faulty doors are undetected and are ultimately sold to consumers.
In another prior art method, developed by the assignee of the current invention and currently used in a small number of assembly plants, an actuator arm is mounted in a fixed position to engage with an open door as a vehicle passes through the test station on the assembly line. The actuator, upon engagement with a door, extends with a constant force and pushes the door toward its closed position. The vehicle's door is then manually inspected to determine if it completely closed and properly engaged the latch mechanism. While this semi-automated method permits testing of all vehicles on an assembly line without removing the vehicles to conduct the test, it suffers from disadvantages as well. For example, the method does not account for vehicles which may be mispositioned or misaligned on the assembly line, and, the method does not permit the testing of the final closing velocity of the door.
Thus, the aforementioned methods and systems do not guarantee a precise measurement of the velocity with which the door engages the latch mechanism, and cannot precisely determine whether an automobile door has been properly installed and aligned without further manual intervention. Therefore, there is a continuing need for an efficient and effective apparatus to verify that a door has been properly manufactured, installed and aligned on a vehicle. Preferably such a system would allow the initial door closing velocity to be directly controlled and/or measured and would automatically measure the final door closing velocity. Variations in a vehicle's position and orientation would be taken into account. Furthermore, the preferred apparatus would also determine if the door properly engaged the latch mechanism and was fully closed.